1. Field of the Invention
The present invention relates to a winding roll presser device used in a long material winding process, and to a long material winding method.
2. Description of the Related Art
A long material such as a paper web produced by a paper machine is wound around a reel spool in a winding process. When the diameter of the winding roll reaches a predetermined final winding diameter, a new reel spool is moved from the stand-by position to the winding position. The long material is then cut, and the cut end of the long material is wound around the new reel spool. This procedure will be hereinafter referred to as xe2x80x9cframe changexe2x80x9d. The last end of the long material that has just been cut off stays on the winding roll, and, then, is moved to the discharge position together with the winding roll. In the discharge position, the winding roll is sent to the next process.
Where the long material is cut at the time of frame change as described above, the winding roll rotates under its own inertia even after the rotation of the reel spool is stopped. As a result, the last cut end of the long material flaps, causing slackness equivalent to a few circles on the outer periphery of the winding roll. The slacked part of the winding roll cannot have sufficient tension, even when the winding roll is set to a rewinding device. With the slackness of the winding roll, a slitting operation cannot be performed. In a case where the long material is coated paper, the coating is damaged due to the rubbing, and the long material can no longer have a commercial value. To maintain the commercial value of the long material, the slacked part is cut off manually, and becomes a waste paper.
Various methods have been suggested to prevent the slackness of paper and reduce paper loss. For instance, Japanese Laid-Open Patent Application Nos. 2000-264511, 2000-264505, and 11-29250 disclose methods in which the winding roll is pressed by a press roll or a brush to prevent the flapping of the last cut end of the paper web. Japanese Laid-Open Patent Application No. 11-29247 discloses a method in which a groove is formed through the windup reference roll (a reel drum) of the winding roll, so that the air caught between the layers of the winding roll can be exhausted through the groove.
However, neither a roller nor a brush can give the winding roll a linear pressure (a pressure per unit length in the width direction) that is sufficient to prevent slackness of paper and reduce paper loss. If a great pressure were given by the roller or the brush, the pressure concentrates in a narrow area, and reduces the quality of the long material. In a worst case, the long material might be ripped due to the pressure.
There has been a method in which the diameter of a roll for pressing is increased so as to widen the contact area and disperse the linear pressure. In this method, however, the inertia of the press roll becomes larger, resulting in higher production costs and running costs. For instance, Japanese Patent Publication No. 6-94319 discloses a method in which an endless support web device is employed to support the winding roll over a wide area. In this method, however, the winding roll is supported by its own weight from below. To endure the weight of the winding roll, the support web device must be very large in size, and therefore requires a very large space.
Accordingly, it is a general object of the present invention to provide a novel and useful winding roll presser device used in a long material winding process and a long material winding method.
Another and more specific object of the present invention is to provide a winding roll presser device and a long material winding method that can reduce loss of paper.
The above objects of the present invention are achieved by A winding roll presser device that presses a winding roll by the entire width thereof, the winding roll being formed by a reel spool and a long material wound therearound, said device including a plurality of rotational rolls arranged in parallel with one another in the width direction, a belt tensely wound so as to cover the plurality of rotational rolls, a first drive unit for moving the belt from a stand-by position so as to bring the belt into contact with the winding roll, and a second drive unit for pressing the winding roll with a straight part of the belt.
The above objects of the present invention are also achieved by a method of winding a long material around a winding roll via a nip, in which the long material is transported on the reel drum and the nip is formed by the winding roll contacting the reel drum, said method comprising the steps of: a) rotating a winding roll presser device that presses the winding roll by the entire width thereof, at a speed equivalent to the rotational speed of the outer periphery of the winding roll; b) bringing the winding roll presser device from a stand-by position into contact with the outer periphery of the winding roll by a predetermined length in the transporting direction of the long material; c) increasing a linear pressure on the winding roll presser device to a predetermined level; d) cutting the long material before the reel drum; e) separating the winding roll from the reel drum after a linear pressure on the nip is reduced to zero; and f) stopping the rotation of the winding roll and the winding roll presser device.
With the above device and method in accordance with the present invention, the belt is brought into contact with the winding roll by a longer length in the transporting direction of the long material, because a wide and straight part of the belt contacts the winding roll. Accordingly, the linear pressure can be dispersed more effectively, compared with a case where a simple roll is brought into contact with a winding roll. As a result, the long material is not ripped or damaged despite the high linear pressure, and the high quality of the product is maintained. Thus, loss of paper can be reduced. Furthermore, since the belt is made of soft reinforced rubber, slackness of the winding roll can be prevented by the high linear pressure during the winding, while the high quality of the long material is maintained. Generally, paper loss of approximately 3000 m is caused, but, in accordance with the present invention, the paper loss can be reduced to 1000 m or less. The linear pressure is preferably in the range of 300 N/m through 3000 N/m in accordance with the present invention.
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.